4K Video Downloader is a video and audio downloader for YouTube, Vimeo, Facebook, Dailymotion, Metacafe, and other video-sharing services. It features video quality up to 4k resolution, FLV, MP4, and MKV support, extraction of audio to the MP3 format, and a "Smart Mode" for fast downloads.

Arx Libertatis is a cross-platform, open source port of Arx Fatalis, a 2002 first-person role-playing game developed by Arkane Studios. Arx Fatalis features crafting, melee and ranged combat, and a unique casting system where the player draws runes in real time to effect the desired spell. The Arx Libertatis source code is based on the publicly released Arx Fatalis sources. This does however not include the game data, so you need to obtain a copy of the original Arx Fatalis or its demo.

Bitcoin is a peer-to-peer electronic cash system that is completely decentralized, without the need for a central server or trusted parties. Users hold the crypto keys to their own money and transact directly with each other, with the help of a P2P network to check for double-spending.

Boost Extras is a set of extraneous libraries for
the Boost environment. It includes an adaptation
of the Boost source to compile with the GNU build
system, a set of classes to handle INI files, and
a class to derive from to use the
boost::intrusive_ptr&lt;&gt;.

ChaiScript is an embedded scripting language designed from the ground up to directly target C++ and take advantage of modern C++ development techniques. Being a native C++ application, it has some advantages over existing embedded scripting languages. It uses a header-only approach, which makes it easy to integrate with existing projects. It maintains type safety between your C++ application and user scripts. It supports a variety of C++ techniques including callbacks, overloaded functions, class methods, and STL containers.

Chesley is a chess engine targeting Unix-like platforms and the xboard GUI. It implements a number of modern chess programming techniques, including bitboard move generation, transposition tables, etc.

EncFS is an encrypted pass-through filesystem
which runs in userspace on Linux (using the FUSE
kernel module). Similar in design to CFS and other
pass-through filesystems, all data is encrypted
and stored in the underlying filesystem. Unlike
loopback filesystems, there is no predetermined or
pre-allocated filesystem size.